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格陵兰冰架在融化，但比过去估计的慢？

格陵兰岛冰架研究的新结果显示，与过去的研究结果类似，冰架正在以令人担忧的速度消失，但是用一个不同的方法做的数据分析得出的新估计提出，冰消失的量比过去认为的要少些。Scott Luthcke和同事分析了来自GRACE卫星的数据，这些卫星测量地球系统变化所引起的微小引力变化。他们分析了其他人曾研究过的同样的GRACE数据，但是所用的方法不同，这使他们能够确定出不同流域系统的行为，而不是把冰架当成一个整体。他们的结果表明，从2003年到2005年格陵兰岛每年消失的冰约为100立方英里。其它的估计曾把同一时期的冰消失量的定在240立方英里。但是这两个估计都与冰架体积在1990年代基本没有变化的其他研究形成鲜明的对比。文章作者和其他研究者一样发现了冰架在边缘在变薄，但是其中心部分有所增加。一篇相关的研究评述讨论了这项新研究以及过去两项对GRACE数据研究的结果。

科学特快报告：Recent Greenland Ice Mass Loss by Drainage System from Satellite Gravity Observations, S. B. Luthcke, et al.
科学特快研究评述：How Fast Are The Ice Sheets Melting?, Anny Cazenave

与老年黄斑病变有关的单核苷酸多态性

老年黄斑病变（AMD）是导致50岁以上的人失明的最常见的原因，它部分的原因是继承了易感基因。在AMD中，视网膜中的感光细胞受损，导致中央视觉逐渐消失。AMD有两种：湿型和乾型。湿型AMD对患者危害最严重，因为视觉消失的速度很快。现在两个研究小组分别报告了对一个新易感基因的互补的研究结果。DeWan 和同事通过研究一个华人人口群，在HTRA1基因中找到了一个使患湿型AMD风险大为增加的单核苷酸多态性（SNP）。SNPs是个体之间基因组的单字母A，T，C 或G的变异。HTRA1 基因编码一个热休克丝氨酸蛋白酶，SNP位于该基因的启动子区域。Zhenglin Yang和同事发现，同一个SNP也增加一个白种人口群患AMD的风险，而且该SNP与HTRA1信使RNA和蛋白的过度表达有关。有关这个基因突变的发现最终将有助于改进AMD的诊断和治疗。

科学特快报告：HTRA1 Promoter Polymorphism in Wet Age-Related Macular Degeneration, Andrew DeWan, et al.
科学特快报告：A Variant of the HTRA1 Gene Increases Susceptibility to Age-Related Macular Degeneration, Zhenglin Yang, et al.

Published Online October 19, 2006
Science DOI: 10.1126/science.1133811
Science Express Index

Reports
Submitted on August 14, 2006
Accepted on October 6, 2006

A Variant of the HTRA1 Gene Increases Susceptibility to Age-Related Macular Degeneration
Zhenglin Yang 1, Nicola J. Camp 2, Hui Sun 3, Zongzhong Tong 4, Daniel Gibbs 4, D. Joshua Cameron 4, Haoyu Chen 4, Yu Zhao 4, Erik Pearson 4, Xi Li 4, Jeremy Chien 5, Andrew DeWan 6, Jennifer Harmon 4, Paul S. Bernstein 7, Viji Shridhar 8, Norman A. Zabriskie 7, Josephine Hoh 6, Kimberly Howes 7, Kang Zhang 4*
1 Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT 84132; Program in Human Molecular Biology and Genetics, Eccles Institute of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84132; Sichuan Medical Science Academy and Sichuan Provincial People's Hospital, Sichuan 610071, China.
2 Division of Genetic Epidemiology, Department of Biomedical Informatics, University of Utah School of Medicine, Salt Lake City, UT 84108 USA.
3 Department of Physiology and Jules Stein Eye Institute, School of Medicine at UCLA, Los Angles, CA 90095 USA.
4 Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT 84132 USA; Program in Human Molecular Biology and Genetics, Eccles Institute of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84132 USA.
5 Department of Laboratory Medicine and Experimental Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
6 Department of Epidemiology and Public Health, Yale University, New Haven, CT 06520 USA.
7 Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT 84132 USA.
8 Department of Laboratory Medicine and Experimental Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905 USA.

* To whom correspondence should be addressed.
Kang Zhang , E-mail: kzhang@hmbg.utah.edu

Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss in the developed world and has a significant genetic predisposition. A locus at human chromosome 10q26 affects the risk of AMD, but the precise gene have not been identified. We genotyped 581 AMD cases and 309 normal controls in a Caucasian cohort in Utah. We demonstrate that a single nucleotide polymorphism (SNP) rs11200638 in the promoter region of HTRA1 is the most likely causal variant for AMD at 10q26 and is estimated to confer a population attributable risk of 49.3%. The HTRA1 gene encodes a secreted serine protease. Preliminary analysis of lymphocytes and retinal pigment epithelium from three AMD patients revealed that the risk allele was associated with elevated expression levels of HTRA1 mRNA and protein. We also found that drusen in the eyes of three AMD patients were strongly immunolabeled with HTRA1 antibody.

微波段的隐身器

研究人员首次发明了一个隐身设备，原则性地演示了如何将物体隐蔽起来，躲过电磁辐射的探测。D. Shurig和同事用超常介质（metamaterials）- 指通过设计操纵其纳米结构来调节其电磁性质的人工组合物-制造了一个空间，该空间能排斥电磁辐射或使电磁辐射好像物体不存在似地通过。研究人员用将一个铜圆柱放到一个在微波频率段工作的人工超常介质的掩盖结构中演示了这个隐身机制。这个掩盖结构降低了来自其中所藏物体的散射，同时减少了其影子，使得掩盖结构与其中的物体有点像自由空间。这个掩盖不是完美的，而且只是二维的，但是它既降低了向前的散射（反射），也减少了向后的散射（影子）。
科学特快报告：Metamaterial Electromagnetic Cloak at Microwave Frequencies, D. Schurig, et al.

宇宙线与银河系一路同行

一个中国和日本的研究小组报告说，接近光速行走的宇宙线，与星际气体和恒星一样绕银河系中心旋转。人们普遍认为这些高能量（高达千万亿电子伏特）的带电粒子流产生加速于众多天体爆炸和高速气体流动（比如超新星爆发和星风）所引发的磁流体激波，但是单个宇宙线带电粒子的传播路径会被湍动的星际磁场搅乱，从而难以确定它们的发源地。9年来,该实验合作组用位于海拔4300米的西藏羊八井宇宙线观测站的大气簇射探测器阵列，记录了近四百亿次的宇宙线粒子事件。对如此大量数据的分析清晰表明，宇宙线具有微弱的各向异性，即其强度随宇宙线的到达方向不同而变化（大约为千分之一的差别），其中包括一个新的靠近Cygnus天区方向上的大尺度的增强。这些实验结果有可能带来对宇宙线、超新星、银河磁场、以及太阳系和银河系动力系统的更好了解。

研究文章：Anisotropy and Corotation of Galactic Cosmic Rays, M. Amenomori, et al.
研究评述：Cosmic Rays Track the Rotation of the Milky Way, Marc Duldig

Anisotropy and Corotation of Galactic Cosmic Rays
M. Amenomori,1 S. Ayabe,2 X. J. Bi,3 D. Chen,4 S. W. Cui,5 Danzengluobu,6 L. K. Ding,3 X. H. Ding,6 C. F. Feng,7 Zhaoyang Feng,3 Z. Y. Feng,8 X. Y. Gao,9 Q. X. Geng,9 H. W. Guo,6 H. H. He,3 M. He,7 K. Hibino,10 N. Hotta,11 Haibing Hu,6 H. B. Hu,3 J. Huang,12 Q. Huang,8 H. Y. Jia,8 F. Kajino,13 K. Kasahara,14 Y. Katayose,4 C. Kato,15 K. Kawata,12 Labaciren,6 G. M. Le,16 A. F. Li,7 J. Y. Li,7 Y.-Q. Lou,17 H. Lu,3 S. L. Lu,3 X. R. Meng,6 K. Mizutani,2,18 J. Mu,9 K. Munakata,15 A. Nagai,19 H. Nanjo,1 M. Nishizawa,20 M. Ohnishi,12 I. Ohta,21 H. Onuma,2 T. Ouchi,10 S. Ozawa,12 J. R. Ren,3 T. Saito,22 T. Y. Saito,12 M. Sakata,13 T. K. Sako,12 T. Sasaki,10 M. Shibata,4 A. Shiomi,12 T. Shirai,10 H. Sugimoto,23 M. Takita,12 Y. H. Tan,3 N. Tateyama,10 S. Torii,18 H. Tsuchiya,24 S. Udo,12 B. Wang,9 H. Wang,3 X. Wang,12 Y. G. Wang,7 H. R. Wu,3 L. Xue,7 Y. Yamamoto,13 C. T. Yan,12 X. C. Yang,9 S. Yasue,25 Z. H. Ye,16 G. C. Yu,8 A. F. Yuan,6 T. Yuda,10 H. M. Zhang,3 J. L. Zhang,3 N. J. Zhang,7 X. Y. Zhang,7 Y. Zhang,3 Yi Zhang,3* Zhaxisangzhu,6 X. X. Zhou8 (The Tibet AS Collaboration)
The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

1 Department of Physics, Hirosaki University, Hirosaki 036-8561, Japan.
2 Department of Physics, Saitama University, Saitama 338-8570, Japan.
3 Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
4 Faculty of Engineering, Yokohama National University, Yokohama 240-8501, Japan.
5 Department of Physics, Hebei Normal University, Shijiazhuang 050016, China.
6 Department of Mathematics and Physics, Tibet University, Lhasa 850000, China.
7 Department of Physics, Shandong University, Jinan 250100, China.
8 Institute of Modern Physics, SouthWest Jiaotong University, Chengdu 610031, China.
9 Department of Physics, Yunnan University, Kunming 650091, China.
10 Faculty of Engineering, Kanagawa University, Yokohama 221-8686, Japan.
11 Faculty of Education, Utsunomiya University, Utsunomiya 321-8505, Japan.
12 Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582, Japan.
13 Department of Physics, Konan University, Kobe 658-8501, Japan.
14 Faculty of Systems Engineering, Shibaura Institute of Technology, Saitama 337-8570, Japan.
15 Department of Physics, Shinshu University, Matsumoto 390-8621, Japan.
16 Center of Space Science and Application Research, Chinese Academy of Sciences, Beijing 100080, China.
17 Physics Department and Tsinghua Center for Astrophysics, Tsinghua University, Beijing 100084, China.
18 Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
19 Advanced Media Network Center, Utsunomiya University, Utsunomiya 321-8585, Japan.
20 National Institute of Informatics, Tokyo 101-8430, Japan.
21 Tochigi Study Center, University of the Air, Utsunomiya 321-0943, Japan.
22 Tokyo Metropolitan College of Industrial Technology, Tokyo 116-8523, Japan.
23 Shonan Institute of Technology, Fujisawa 251-8511, Japan.
24 RIKEN, Wako 351-0198, Japan.
25 School of General Education, Shinshu University, Matsumoto 390-8621, Japan.

* To whom correspondence should be addressed. E-mail: zhangyi@mail.ihep.ac.cn

生活在地球深处黑暗中的古老生命

科学家报告说，几千万年来，细菌一直生活在地球表面下的深处，与太阳光没有联系。当工程师在南非的一个金矿钻进到2.8公里深处的一个水层中后，Li-Hung Lin和同事对水层和矿的其他地方进行了采样。他们发现了Firmicute门的一种靠降解硫酸盐化合物为能源的细菌。这些生物体似乎完全独立于任何与光合作用有关的能源。文章作者说，与此相比，许多过去研究过的表面下微生物生态系统一般在地表1公里以上的深度，它们间接地与太阳光有关系。虽然微生物能在地球深处生存已经是众所周知，但是这项研究应该能帮助回答有关这些群落的丰富程度、多样性、以及存在了多长时间等问题。

报告：Long-Term Sustainability of a High-Energy, Low-Diversity Crustal Biome, Li-Hung Lin, et al.

Long-Term Sustainability of a High-Energy, Low-Diversity Crustal Biome
Li-Hung Lin,1,2* Pei-Ling Wang,3 Douglas Rumble,4 Johanna Lippmann-Pipke,5 Erik Boice,6 Lisa M. Pratt,6 Barbara Sherwood Lollar,7 Eoin L. Brodie,8 Terry C. Hazen,8 Gary L. Andersen,8 Todd Z. DeSantis,8 Duane P. Moser,9 Dave Kershaw,10 T. C. Onstott1
Geochemical, microbiological, and molecular analyses of alkaline saline groundwater at 2.8 kilometers depth in Archaean metabasalt revealed a microbial biome dominated by a single phylotype affiliated with thermophilic sulfate reducers belonging to Firmicutes. These sulfate reducers were sustained by geologically produced sulfate and hydrogen at concentrations sufficient to maintain activities for millions of years with no apparent reliance on photosynthetically derived substrates.

1 Department of Geosciences, Princeton University, Princeton, NJ, USA.
2 Department of Geosciences, National Taiwan University, Taipei, Taiwan.
3 Institute of Oceanography, National Taiwan University, Taipei, Taiwan.
4 Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, USA.
5 GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, Germany.
6 Department of Geological Sciences, Indiana University, Bloomington, IN, USA.
7 Department of Geology, University of Toronto, Toronto, ON, Canada.
8 Ecology Department, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
9 Division of Earth and Ecosystems Sciences, Desert Research Institute, Las Vegas, NV, USA.
10 Mponeng Mine, Anglo Gold, Johannesburg, South Africa.

* To whom correspondence should be addressed. E-mail: lhlin@ntu.edu.tw

提高磁共振成像的灵敏度

被广泛用于人体组织成像的MRI仪器也许有朝一日能显示出身体中的单个分子的位置。这个信息将能够给医生提供检查和治疗疾病的新机会。Leif Schroder和同事发展了一种基于氙而不是氢的MRI技术，把灵敏度提高了大约1万倍。常规MRI用一个磁场线圈来检测水分子中的氢原子，氢原子核响应电磁波脉冲而翻转从而解释其在身体中的存在，但是这个技术只能检测比较大量的水。本文作者构造了包含“超极化的”氙原子的分子笼子，氙更容易被MRI探测到。一个涉及氙原子进出笼子的复杂的检测方法使测量变得更敏感。附加在笼子上的特定的结合分子会使笼子锁到身体中的特定表面上。作者用他们的技术检测了少量的散布在液体中的琼脂糖球。在一篇相关的研究评述中，Bastiaan Driehuys描述了这个方法如何有朝一日能用来检测病人的心脏病。

报告：Molecular Imaging Using a Targeted Magnetic Resonance Hyperpolarized Biosensor, Leif Schroder, Thomas J. Lowery, Christian Hilty, David E. Wemmer, and Alexander Pines
研究评述：Toward Molecular Imaging with Xenon MRI, Bastiaan Driehuys


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